Flat-bed letterpress printing machines



4, 1965 A. w. RANGER 3,202,096

FLAT-BED LETTERPRESS PRINTING MACHINES Filed Feb. 20, 1965 6 Sheets-Sheet 1 1 a I/ A 2 g ET 9 N m n J Aug. 24, 1965 A. w. RANGER 3,202,095

FLAT-BED LETTERPRESS PRINTING MACHINES Filed Feb. 20, 1963 6 Sheets-Sheet 2 3 0 uminn. "mm F L I, a ll fim .27- Q T 29--- T 1E ZZZ 25 LFB 28 J o l @m: n sum 4 Pg 30 f 29 27 1965 A. w. RANGER 3,202,096

FLAT-BED LETTERPRESS PRINTING MACHINES Filed Feb. 20, 1963 6 Sheets-Sheet 3 1965 A. w. RANGER 3,202,096

FLAT-BED LETTERPRESS PRINTING MACHINES Filed Feb. 20, 1963 e Sheets-Sheet 4 Aug. 24, 1965 A. w. RANGER 3,202,095

FLAT-BED LETTERPRESS PRINTING MACHINES Filed Feb. 20, 1963 6 Sheets-Sheet 5 1965 A. w. RANGER 3,202,096

FLAT-BED LETTERPRESS PRINTING MACHINES Filed Feb. 20, 1963 6 Sheets-Sheet 6 United States Patent 3,262,096 FLAT-BEE) LETTERPRES PRINTING MAGHENES Arthur Willard Ranger, to W. Hill St., Brighton ll, dussex, England Filed Feb. 20, 1963, den. No. 259,813 Claims priority, application Great Britain, Feb. 28, 1962, 7,721/62 8 Claims. (Cl. MEL-25d) This invention relates to flatbed letterpress printing machines of the kind having a main frame, a reciprocatory fiat-bed mounted on the main frame and on which the forrne to be printed is supported during operation of the machine and a printing cylinder carried on the main frame above the flat-bed, the printing cylinder being pressed into engagement with the forme when the flat-bed travels in the direction of movement of the part of the cylinder adjacent the forme and being adapted to clear the forme during return movement of the bed.

Considerable pressure is applied to the forme during the period of the printiru impression and the reciprocatory bed on which the forme is carried must be very rigid to accept the pressure as it travels on rollers held in cages which are reciprocated by rack and pinion means and which constitute moving lines of support for the flat-bed. The flat-bed is usually, therefore, constructed as a deeply ribbed casting with a plane upper surface, and of sufficient rigidity to resist deflection under pressure when the supporting rollers are not directly beneath the impressional line. This construction requires considerable metal, and the rapid reciprocation of such a mass improses limitations on speed and necessitates great strength in the reciprocatory mechanism.

An object of the present invention is to provide a flat bed letterpress printing machine of the kind set forth capable of operating at hi her speeds than has been the case hithero. I

A flat-bed letterpress printing machine of the kind set forth, according to the present invention, includes a fiatbed of thin plate metal the underface of which fiatwise engages and is reciprocable upon a plane surface provided on the main frame which surface is interrupted by a lowfriction support for the flat-bed, said support extending parallel with and vertically below the printing cylinder.

Suitably, the low-friction support comprises roller means extending parallel with the printing cylinder, the roller means at uppermost locations thereof being sli htly above the level of the plane surface of the main frame which engages the underface of the flat-bed.

The invention will now be described, by way of example, witl reference to the accompanying drawings, in which:

FEGURE l is a sectional side elevation of a fiat-bed letterpress printing machine according to the invention;

FIGURE 2 is a plan view of the flat-bed of the machine of FIGURE 1;

FIGURE 3 is a sectional view on the line III-Ill of FIGURE 2;

FEGURE 4 is a fragmentary sectional side elevation to a larger scale than that of FIGURE 1 showing features of the machine of FIGURE 1 in greater detail;

FIGURE 5 is a fragmentary sectional view taken on the line VV of FIGURE 4-;

FIGURE 6 is a sectional view taken on the line VI-VI of FIGURE 1;

FIGURES 7 and 8 are respective fragmentary longitudinal and transverse sectional views illustrating a modified construction, FIGURE 7 being taken on the line VII-VII of FIGURE 8 and FIGURE 8 being taken on the line VIll-VIII of FIGURE 7;

FIGURES 9 and 10 are respective fragmentary longitudinal and transverse sectional views illustrating a further modified construction, FIGURE 10 being taken on the line X-X of FIGURE 9; and

EEGURE 11 is a fragmentary longitudinal sectional View showing yet a further modified construction.

Throughout the drawings like parts have been accorded the same reference numerals.

Referring first to FIGURES l to 6 of the drawings, a main frame it of the machine has its upper surface 11 machined to a flat plane in which are formed grooves (not shown) which extend at 45 degrees to the sides of the frame. These grooves form a diamond pattern as viewed in plan. Below the upper surface 11, the frame 10 is formed with deep transverse and longitudinal strengthening ribs 12.

An im ression cylinder 13 is disposed transversely of the main frame ill and is mounted on a shaft 22 carried in bearin s provided on the main frame.

immediately below the cylinder 13, the upper surface ll of the main frame is formed with a trough l4 integral with a cross-girt 15 of the frame and housing a multiple bearing lock 16 having a base member 17 formed in one with upstanding spaced blades 18 which constitute carrier .ipports for a stationary shaft 19 the axis of which is parallel to and in the vertical plane containing the axis of the cylinder shaft 22. The upper surfacesof the bla-ces 18 form continuations of the surface 11 and be tween the blades are rollers 2i each of which is freely rotatably mounted on shaft 15 and has its highest point disposed at a level about one to one and a half thousandths of an inch above the level of the upper surfaces of the blades iii. Stitfening stays 2i connect each pair of blades 18 above and to t e rear of rollers 29.

A forme carriage or reciprocatory flat-bed 25 is made from suitable metal such as steel or aluminum bronze ground flat on both sides and comprises a relatively thin plate the area of which extends a little beyond that occupied by forrne 2s, chase 27, bearers 28, locking bars 29 and racks Fall. The racks fill effect reciprocation of the bed 25 and partial rotation of the impression cylinder 13 through oscillation of a shaft 31 and gear 32 which is keyed to shaft 371, such oscillation being accomplished in known manner, for example, by a prime mover electric motor (not shown) which is coupled as by belts to drive a shaft the latter being coupled by gears to a shaft 34 rotation of which causes oscillatory movement of a rocker arm which carries an arcuate gear in mesh with a gear keyed to shaft 31.

When tie bed is drawn, during the printing stroke, beneath the impression cylinder 13, pressure is exerted by the cylinder on the forms 26 and is transmitted through the bed 25 to the rollers 2d thence to the multiple bearing block lie, the trough Id and finally the cross-girt of the main frame. Preferably, the distance between t e rollers 29 and, therefore, the thickness of the blades 18 is made substantially equal to the thicknessof the bed 25. This means that the pressure exerted by the printing cylinder on the bed at locations above the respective blades is applied to parts of the bed of square or approximately square cross-section and any bending of these parts of the bed under printing pressure is largely, if not wholly, avoided.

It will be apparent to those skilled in the art that the use of a thin, plate metal fiat-bed 25 necessitates the provision on the main frame It) of the machine of a rigid plane surface to support the flat-bed and a low-friction suport, provided by the rollers 20, on the line of impression, the low friction support reducing drag on the bed. Also, the grooves in the surface ll serve to reduce drag on the bed 25 prior and subsequent to the printing impression.

If preferred, the flatbed 25 may be reciprocated, as shown in FIGURES 7 and 8, by means attached to its Patented Aug. 24, 1965- underside. To this end, the plane surface ll, the trough 14 and the multiple bearing block 16 are divided, in a direction longitudinally of the main frame lltl, to form a slot 39 for permitting the passage of a bridge-piece it! secured as by bolts 4-1 to the underside of the fiat-bed 25. The slot 39 accommodates flat-bed reciprocating mechanism of known form (not shown) and, at the line of impression, bridge-piece 40 is suported on rollers 42 which are freely rotatable on stub-axles 43 mounted in the multiple bearing block 16. The bridge-piece is further located by gibs 44- secured to inner opposed faces of the slot and engaging in respective grooves in the sides of the bridge-piece.

If desired, the rollers 26 of the low-friction support may be positively driven in oscillatory fashion during move ment of the fiat-bed. Thus, as shown in FIGURES 9 and each of rollers 21 is secured as by a grub-screw 45 to shaft 19 each end of which has keyed thereto a pinion 46. The pinions 46 mesh with respective sets of rack teeth 47 formed on the underside of the racks 36.

In a further modification, a detail of which is illustrated in FIGURE 11, the trough lid is made substantially deeper and accommodates in the bottom thereof the elements 16 to previously described. Above these elements and mounted in suitable end bearings is a single roller 59. At the upper ends of the inner opposed faces of the trough 14 are respective overhangs 51 having lower surfaces of radius substantially the same as that of roller 50. The overhangs 51 reduce the width of the gap formed in the upper surface 11. The roller 5% may be an idler roller or may be positively driven in the same way as has previously been described in connection with rollers 21). If desired, there may be provided parallel with the axis of roller 5th and in the horizontal plane thereof, one or more further rollers for resisting any tendency of the roller St) to move in the longitudinal direction of the frame 1% when under printing impression.

The use of a thin, plate metal flat-bed as has been described, makes possible the manufacture of letterpress printing machines at lower cost which, since the mass of the reciprocatory bed is substantially reduced, are capable of operating at appreciably higher speeds.

In the case of a conventional flat-bed comprising a ribbed casting measuring x 4-0 X 2 /2 inches, the mass involved is about 350 lbs. Compared with this a plate metal bed measuring 30 x x W inches involves a mass of about 63 lbs. and, by virtue of this considerable reduction in reciprocatory mass an increase of printing speed in the range of 30 to percent is achievable.

Where reference is made hereinbefore to thin, plate metal flat-bed, the term thin should be understood to comprehend plate thicknesses in the range to inches and, preferably, in the range & to A inches.

I claim:

1. A high speed fiat-bed letterpress printing machine comprising:

(a) a main frame having an upper surface which is (b) a fiat-bed of flat thin plate metal having an underface which flatwise engages and is reciprocable upon and in constant engagement with the upper flat surface of the main frame;

(c) the fiat-bed carrying, during operation of the machine, the forme to be printed,

((1) driving means mounted on the main frame for effecting reciprocation of the flat-bed on the fiat surface of the frame; and

(e) an impression cylinder carried on and transversely of the main frame above the flat-bed;

(f) the impression cylinder being pressed into engagement with the forme when the fiat-bed travels in the direction of movement of the part of the cylinder adjacent the forme and being adapted to clear the forme during return movement of the bed;

(g) there being provided in the flat surface of the frame intermediate the ends thereof a low-friction support for the fiat-bed which support extends parallel with and vertically below the impression cylinder so that during the impression stroke the flat-bed is supported by said low-friction support and by parts of the flat upper surface of the mainframe at respective opposite sides of said low-friction support;

(h) said low-friction support comprising roller means extending parallel with the printing cylinder, the roller means at uppermost locations thereof being slightly above the level of the plane surface of the main frame which engages the underface of the fiatbed, said roller means comprising several rollers mounted on a common shaft carried in blades extending upwardly from a block disposed in a transverse trough formed in the plane surface of the main frame, the blades being disposed each between two of the rollers and having respective upper surfaces co-planar with the flat upper surface of the frame.

2. A machine as claimed in claim 1, wherein the thickness of each blade is approximately equal to the thickness of the fiat-bed.

3. A machine as claimed in claim ll, wherein the trough is formed int grally with a cross-girt of the machine.

4. A high speed fiat-bed letterpress printing machine comprising:

(a) a main frame having an upper surface which is (b) a fiat-bed of flat thin plate metal having an underface which fiatwise engages and is reciprocable upon and in constant engagement with the upper flat surface of the main frame;

(0) the fiat-bed carrying, during operation of the machine, the forrne to be printed;

(d) driving means mounted on the main frame for effecting reciprocation of the flat-bed on the fiat surface of the frame;

(e) an impression cylinder carried on and transversely of the main frame above the flat-bed;

(f) the impression cylinder being pressed into engagement with the forme when the flat-bed travels in the direction of movement of the part of the cylinder adjacent the forme and being adapted to clear the forme during return movement of the bed;

(g) there being provided in the fiat surface of the frame intermediate the ends thereof, a low-friction support for the flat-bed which support extends parallel With and vertically below the impression cylinder so that during the impression stroke the flat-bed is supported by said low-friction support and by parts of the flat upper surface of the main frame at respective opposite sides of said low-friction support;

(h) a central longitudinally extending slot formed in the main frame which intersects the low-friction support and in which is engaged at bridge-piece secured to the underface of the flat-bed, said bridge-piece cooperating with means for effecting reciprocation of the flat-bed.

5. A machine as clai ted in claim 4, wherein the bridge piece is formed along opposite sides thereof with grooves in which are engaged respective locating gibs carried on opposite sides of the slot.

6. A high speed flat-bed letterpress printing machine comprising:

(a) a main frame having an upper surface which is flat;

(b) a fiat-bed of flat thin plate metal having an underface which fiatwise engages and is reciprocable upon and in constant engagement with the upper fiat surface of the main frame;

(0) the fiat-bed carrying, during operation of the machine, the forme to be printed;

(d) driving means mounted on the main frame for effecting reciprocation of the fiat-bed on the flat surface of the frame; and

(e) an impression cylinder carried on and transversely of the main frame above the flat-bed;

(f) the impression cylinder being pressed into engagement with the forme when the flat-bed travels in the direction of movement of the part of the cylinder adjacent the forme and being adapted to clear the forme during return movement of the bed;

(g) there being provided in the flat surface of the frame intermediate the ends thereof a low-friction support for the flat-bed which support extends parallel with and vertically below the impression cylinder, so that during the impression stroke the flat-bed is supported by said low-friction support and by parts of the flat upper surface of the main frame at respective opposite sides of said low-friction support;

(b) said low-friction support comprising a single roller disposed with its axis in the vertical plane containing the printing cylinder axis, the single roller being contained in a transverse trough formed in the plane surface of the main frame and being arranged with its uppermost point slightly above the level of the plane surface, said trough having sides with upper ends which are formed with respective overhangs each having an inner surface of radius substantially corresponding with that of the single roller.

7. A high speed fiat-bed letterpress printing machine comprising (a) a main frame having an upper surface which is flat;

(b) a flat-bed of flat thin plate metal having an under- 0 face which flatwise engages and is reciprocable upon and in constant engagement with the upper flat surface of the main frame;

(c) the fiat-bed carrying, during operation of the ma chine, the forme to be printed;

(d) driving means mounted on the main frame for effecting reciprocation of the flat-bed on the flat surface of the frame; and

(e) an impression cylinder carried on and transversely of the main frame above the flat-bed;

(f) the impression cylinder being pressed into engagernent with the forme when the flat-bed travels in the direction of movement of the part of the cylinder adjacent the forme and being adapted to clear the forme during return movement of the bed;

(g) there being provided in the flat surface of the frame intermediate the ends thereof a low-friction support for the fiat-bed which support extends parallel with and vertically below the impression cylinder, so that during the impression stroke the fiat-bed is supported by said low friction support and by parts of the flat upper surface of the main frame at respective opposite sides of said low friction support;

(h) said low friction support comprising a single roller disposed with its axis in the Vertical plane containing the printing cylinder axis, the single roller being contained in a transverse trough formed in the plane surface of the main frame and being arranged with its uppermost point slightly above the level of the plane surface, said single roller being supported at least partly by a plurality of rollers disposed in the trough below the single roller and mounted on a common shaft carried in blades extending upwardly from a block disposed in the bottom of the trough.

8. A machine as claimed in claim 1, wherein each roller is fixed relative to the common shaft which carries pinion means keyed thereto and engagcable with rack teeth on the underside of the fiat-bed whereby the rollers of the low-friction support are reciprocatorily rotated during reciprocation of the flat-bed.

References Cited by the Examiner UNITED STATES PATENTS 3/32 Great Britain.

ROBERT E. PULFREY, Primary Examiner. EUGENE R. CAPOZIO, Examiner, 

1. A HIGH SPEED FLAT-BED LETTERPRESS PRINTING MACHINE COMPRISING: (A) A MAIN FRAME HAVING AN UPPER SURFACE WHICH IS FLAT; (B) A FLAT-BED OF FLAT THIN PLATE METAL HAVING AN UNDERFACE WHICH FLATWISE ENGAGES AND IS RECIPROCABLE UPON AND IN CONSTANT ENGAGEMENT WITH THE UPPER FLAT SURFACE OF THE MAIN FRAME; (C) THE FLAT-BED CARRYING, DURING OPERATION OF THE MACHINE, THE FORME TO BE PRINTED, (D) DRIVING MEANS MOUNTED ON THE MAIN FRAME FOR EFFECTING RECIPROCATION OF THE FLAT-BED ON THE FLAT SURFACE OF THE FRAME; AND (E) AN IMPRESSION DYLINDER CARRIED ON AND TRANSVERSELY OF THE MAIN FRAME ABOVE THE FLAT-BED; (F) THE IMPRESSION CYLINDER BEING PRESSED INTO ENGAGEMENT WITH THE FORME WHEN THE FLAT-BED TRAVELS IN THE DIRECTION OF MOVEMENT OF THE PART OF THE CYLINDER ADJACENT THE FORME AND BEING ADAPTED TO CLEAR THE FORME DURING RETURN MOVEMENT OF THE BED; (G) THERE BEING PROVIDED IN THE FLAT SURFACE OF THE FRAME INTERMEDIATE THE ENDS THEREOF A LOWER-FRICTION SUPPORT FOR THE FLAT-BED WHICH SUPPORT EXTENDS PARALLEL WITH AND VERTICALLY BELOW THE IMPRESSION CYLINDER SO THAT DURING THE IMPRESSION STROKE THE FLAT-BED IS SUPPORTED BY SAID LOW-FRICTION SUPPORT AND BY PARTS OF THE FLAT UPPER SURFACE OF THE MAIN FRAME AT RESPECTIVE OPPOSITE SIDES OF SAID LOW-FRICTION SUPPORT; (H) SAID LOW-FRICTION SUPPORT COMPRISING ROLLER MEANS EXTENDING PARALLEL WITH THE PRINTING CYLINDER, THE ROLLER MEANS AT UPPERMOST LOCATIONS THEREOF BEING SLIGHTLY ABOVE THE LVEL OF THE PLANE SURFACE OF THE MAIN FRAME WHICH ENGAGES THE UNDERFACE OF THE FLATBED, SAID ROLLER MEANS COMPRISING SEVERAL ROLLERS MOUNTED ON A COMMON SHAFT CARRIED IN BLADES EXTENDING UPWARDLY FROM A BLOCK DISPOSED IN A TRANSVERSE THROUGH FORMED IN THE PLANE SURFACE OF THE MAIN FRAME, THE BLADES BEING DISPOSED EACH BETWEEN TWO OF THE ROLLERS AND HAVING RESPECTIVE UPPER SURFACES CO-PLANAR WITH THE FLAT UPPER SURFACE OF THE FRAME. 